


The Mysterious Roommate

by NinjaSpaz



Category: Haikyuu!!
Genre: Business Major Kenma, Day 4 University AU, Day 5 Didn't Know They Were Dating, Domestic Fluff, Fluff, Gamer kenma, I continue to push my long haired kuroo agenda, I wrote this in a manic frenzy, Kenma is a little shit, Kenma is incredibly patient, KuroKen Week 2020, Kuroo's Students will be the death of him, M/M, Pining, TA Kuroo, kuroo is oblivious, not edited
Language: English
Status: Completed
Published: 2020-04-18
Updated: 2020-04-18
Packaged: 2021-02-23 14:35:17
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,356
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23713051
Author URL: https://archiveofourown.org/users/NinjaSpaz/pseuds/NinjaSpaz
Summary: Kuroo has a reputation as "the hot chem TA." His latest batch of freshman students make a discovery that threatens to turn his world upside down.Or: The University AU in which Kuroo didn't know he and Kenma have been dating for years.
Relationships: Kozume Kenma/Kuroo Tetsurou
Comments: 32
Kudos: 451
Collections: Kuroken Week 2020, kuroken lol screaming





	The Mysterious Roommate

**Author's Note:**

> So I missed Day 4 (University AU) because of lingering effects of a migraine and decided I could combine it with Day 5 (Didn't Know They Were Dating) anyway. Instead of doing two short Twitter thread fics, I give you one medium-ish one shot fic exclusively here on ao3.

“Careful with that flask!” Kuroo cried at a small blonde freshman who nearly tripped over her untied shoelaces with a soft squeak. His TA instincts had him at her side in an instant to steady her before she, and her chemical solution, could tumble to the floor. “Sakura-chan, what have I said about lab safety, hmm?”

The girl’s face turned crimson behind her safety glasses. “S-sorry, Kuroo-senpai.” She handed the flask to her partner, a brunette whose face was equally red from second-hand embarrassment—or maybe it was jealousy, these freshman girls could be vicious about getting his attention—as she knelt to tighten her laces.

“It would have been a shame if we’d had to hose Akane-chan in the chemical shower,” he said, smirking at her lab partner. The flask would have doused her for sure if he hadn’t been so quick on his feet. Akane flushed brighter, turning away from him as she added the solution to their experiment.

“Won’t happen again!” Sakura laughed nervously.

Kuroo nodded. “I have the utmost faith in you both. Watch that, now, don’t let it boil over,” he added as Akane poured a little too brusquely. He helped the pair through the next step until their nerves had settled and their hands weren’t trembling so much. He’d learned the hard way his first semester as a TA to stay for a moment before moving on to supervise other groups.

He was used to the stares and the giggles by now. Every semester started the same. This was his third as TA for Intro to Chemistry, a required class for all incoming freshman in any of the science programs. As a grad student, they were fascinated and charmed by him without him even having to lift a finger. He was an enigma, another new sight they got to experience as part of their new university life. The first month of labs and discussions were an adjustment period for them as much as for him. Eventually it would settle down though and they would be so overwhelmed by all their work they wouldn’t even have time to spare for thoughts of the “hot chem TA.”

He tried to make himself less appealing by always wearing sweater vests and button-downs in class, and keeping his untamable mane restrained with a thick elastic tie, but somehow that just added to his charm. Bokuto had teased him that it was because he was still built like a jock, no matter how nerdy he tried to make himself look.

“I don’t even practice every day anymore,” he had moaned. “I barely have time for the Wednesday and Saturday practices I _do_ go to.” He didn’t play competitively anymore either, just intramurals with a local club that had games every Sunday. Something to keep him fit and as a break from his grad school work.

“Yeah but dude, you’re still jacked.” Bokuto had laughed at his pained expression. “Bro, you could easily join in one of our practices and wipe the floor with any of our opponents.”

“Yeah, right,” Kuroo scoffed. Bokuto was moving up in the pros, playing V2 and he had a real shot at a V1 team in the fall.

They still Skyped a few times a week to stay updated with their lives and lament their woes to each other, and Bokuto was becoming familiar with the early semester antics Kuroo had to put up with. “Just give it a couple more weeks and they’ll realize what a massive nerd you are just from listening to you talk.”

Kuroo rolled his eyes. “Oh you know what? I think I hear Kenma calling me. Goodnight Bo!”

“Give him my love!” Bokuto snarked back, knowing full well Kuroo was alone in his office and that he would, in fact, give Kenma Bo’s love once he got home.

Kuroo sighed as he collected his section’s lab reports and piled them into his messenger bag. He could grade them at home while watching a movie. He glanced at the clock and winced. It was already after 9pm, which meant Kenma had probably forgotten to eat while streaming. It would be too late to start cooking once he got back, so he swung through the late-night café and grabbed a couple hot sandwiches and energy drinks. It was likely going to be a long night for both of them.

“I’m home,” he sighed as he toed off his sneakers in the vestibule. He could hear the soft button clacking from the other room as Kenma played some new JRPG he’d been waiting years for. “Kenma, I brought food.” A pause. Then a soft voice announced that he would be taking a short break to stretch and that he’d be back soon.

There were two things that could make Kenma put down a game, as Kuroo learned over the two and a half years they’d roomed together. One was food, especially when he hadn’t eaten all day because he was so immersed in his game. The other was the threat of Kuroo popping up on his stream and setting off a flurry of comments about “the mysterious dark-haired roommate.” Kuroo announcing he had food was good for both, because if Kenma didn’t pause his game, Kuroo absolutely would go in and force him to eat on stream.

“Welcome home,” his childhood best friend said as he emerged from his room. His hair was tied in a loose bun at the base of his neck, the bleached ends of two stubborn chunks framing his face. He was wearing Kuroo’s university sweatshirt over his old Nekoma gym shorts. “Long day at the office?”

“Har har,” Kuroo said, tossing one of the sandwiches Kenma’s way. “Almost had to file an accident report because these children can’t seem to keep it together in my lab.”

Kenma chuckled as he unwrapped the steaming bun. “Again? Was it at least one of the girls this time?”

“Yeah,” he sighed. Kuroo wasn’t sure why that mattered, he’d had young men come onto him as often as the young women, but Kenma always seemed more annoyed when it was the guys. “Loose shoelaces of all things. Who makes it all the way to one the most prestigious universities in Tokyo and can’t tie their shoelaces?”

Kenma shrugged. “Well, they’ll get over it once they realize you’re not as cool as you look.”

Kuroo clapped a hand over his heart. “Et tu? You wound me, Kenma.” He fell dramatically over the shorter man’s shoulders, eliciting another soft chuckle. “How long have you been streaming?”

“Hmm.” Kenma checked the clock in the kitchen. “Bout 7 hours, give or take.”

Kuroo did some quick math in his head. He frowned. “That means you skipped your 3pm Econometrics lecture.”

“Please,” Kenma snorted. “Ye of little faith.” He fixed Kuroo with a piercing look, golden eyes flashing indignation. “The prof’s kid was sick and his wife had to work second shift so he canceled class today.”

“Oh.”

Kenma wrapped up the other half of his sandwich and moved to the kitchen to put it in the fridge for a late-night snack. “You got a lot of work to do yet tonight?”

“Just grading some lab reports and homework assignments. I’ve got a thesis update due on Monday but I can start that tomorrow.”

“K. I’ll wrap up in there and then we can watch that new Netflix documentary if you want.”

“Sure.” He set his bags down by the couch and went to his room to change into more comfortable clothes. He didn’t mind the sweater vests but when he was home, he preferred leisurewear. He threw on a tank and his own volleyball shorts. Kenma would get a kick out of their matching set.

“Oh now you’re just copying me,” the younger man said when he emerged from his room twenty minutes later with his PSP.

“What? I always wear these around the house.”

“Uh-huh.” Kenma settled on the couch next to him. “And what’s your excuse for your hair?”

“What’s wrong with my hair?” Kenma gave him a blank stare. He sighed. “I thought maybe it would help,” he muttered before yanking the elastic and letting his hair fall to his shoulders.

“We can’t all pull off the hobo look,” Kenma snickered. “If you’re not careful they’re gonna think you’re a closet Kodzuken fan.”

Kuroo rolled his eyes. “I am not in the closet.”

“Of course you’re not.” He didn’t object as Kenma took a brush to his unruly locks and tied it up high and out of his face, the way he preferred it. “Oh, Bo sends his love by the way.”

“He always does,” Kenma chuckled.

An easiness settled in Kuroo’s chest as they fell into their usual routine. He worked on grading, sometimes with snarking commentary about a particularly asinine response, while Kenma played on his PSP and a movie or TV show played on Netflix. As the night went on, his “To Be Graded” pile shrank and his eyes began to droop. It didn’t help that Kenma was so warm leaning against his side. He was rubbing his eyes by the time he finished with the last paper. He didn’t even know what was playing on the TV anymore. He really shouldn’t have tried to stay up so late to finish them, but he would have time to go back over them before his afternoon sections.

“Let’s go to bed,” Kenma said, startling him out of his thoughts. “Friday’s are your early days, right?”

He nodded. He had an 8am lecture and 9am office hours. He looked at the clock. 2am. Crap.

He didn’t protest as Kenma pulled him back to his bedroom. Kuroo fell face first into his pillow, throwing his arm around Kenma as he settled in next to Kuroo. He still had his handheld. “Are you even tired?” Kuroo asked.

“Not really, but if the light’s gonna bother you I’ll sleep in the other room.”

Kuroo instinctively gripped Kenma’s side tighter. “Nah, it’s alright.” He always slept better when Kenma was at his side. Some things hadn’t changed in almost fifteen years.

He slept through his first alarm. And his second alarm. His third alarm was Kenma smacking him over the head with his pillow. “Kuroo, you’re gonna be late!”

“Wha?” He squinted at his phone. 730am. “Oh shit!” It took him twenty minutes to get to class from their apartment. Kenma groaned and pulled the blanket over his head as Kuroo scrambled out of bed and into the cleanest pants on the floor. He grabbed a button-down out of his closet and brushed his teeth. He could grab breakfast at school before his office hours.

He barely made it to class with a minute to spare. Hanako-san giggled as he slid into his seat at the back. “Rough morning?” she whispered, pointing to his hair.

“Overslept,” he groaned. “Don’t suppose you have a spare brush I can borrow?” He was sure he looked like a rooster again. Growing his hair out hadn’t kept that particular shape from forming with his bangs.

Hanako smirked as she pulled a brush and hair tie from her bag. “It’ll cost you.”

He sighed. “What?”

“I’m going home for a visit next weekend, my sister’s wedding.” Her grin dripped with honey. “Could you cover my lab section so I can head out early?”

Kuroo snatched the brush from her hand and brandished it at her like a blade. “This is extortion.”

“Is that a ‘yes Rika-chan I would be glad to help you?’ or do I need to resort to drastic measures?”

He shook his head as he ran the brush through the knots. “I don’t know how Gin-chan puts up with you.”

She leaned her chin in her hand and continued to grin at him. “Probably the same way Kenma-san puts up with you.”

He didn’t get a chance to retort that his relationship with Kenma was not remotely in the same vein as her relationship with her literal girlfriend because the instructor came in and scolded them. “Last I checked this wasn’t Hairdressing 101, Kuroo-san, Hanako-san.”

Kuroo quickly tied his hair back and gave Rika-chan her brush back with a whispered “Thanks.”

“Friday,” she whispered. “3pm.” He rolled his eyes. She really knew how to twist his arm.

After class he stopped at the campus café and got his much-needed coffee and an assortment of breakfast items and snacks for the morning. He was a few minutes late to his office hours, but no one had scheduled anything with him so he didn’t think anything of it.

He was startled to find Akane-chan and Sakura-chan hovering outside his office door when he arrived fifteen minutes late. “Oh, morning ladies.” They jumped at the sound of his voice, nearly dropping their textbooks. “Sorry I’m late, rough morning. Let me get settled first and then I’ll gladly help you with whatever you require.” He gave them his most courteous smile, and they descended into giggles.

Shaking his head, he unlocked his door and went to his desk. It was still a bit cluttered from his work the previous night so he straightened the paperwork and stuck it in one of the folders in his desk filing cabinet. “Alright girls. What can your senpai do for you this fine morning?”

It turned out they were struggling with balancing chemical equations and following through on their unit conversions. He took the next forty minutes helping them through it until the cogs clicked into place in their minds. Sakura figured it out faster so he had her explain it to Akane to demonstrate her newfound understanding.

If he was being honest, this was his favorite part of being a teaching assistant. When his students suddenly grasped the concepts they were struggling with and are able to help their friends understand it, it made him about as giddy as pulling off a successful read block. After hearing it from both Kuroo and Sakura, Akane had her “Eureka!” moment, too. They celebrated with high fives all around.

They were getting ready to leave when there was a soft knock on his door. The girls’ eyes went as wide as saucers and they seemed to be ready to vibrate out of their skin. He looked up to see Kenma, long-suffering look plastered across his face as he frowned at Kuroo. The older man leapt to his feet. “Kenma? It’s not like you to show up here.”

His best friend waggled a folder in front of his face. “It’s not like you to leave work at home,” he countered.

Oh. OH. He’d left all his graded papers on the coffee table in their living room. That would have been bad. “You’re a lifesaver,” he sighed, taking the folder and flipping through to make sure they were all there.

Kenma’s eyes flitted to the tittering freshman. He gave them a courteous nod before turning back to Kuroo. “Usual tonight?”

Kuroo had to think about what day it was. He really needed another cup of coffee to think straight. Friday’s were his early days, but that meant he was also done by 2pm. Kenma had Business Management until 3pm and then they usually met up at a local bakery where the apple pies were always fresh. After which they would catch a movie or a varsity volleyball game, if they were playing at home, and then ramen at a roadside stand between campus and their apartment.

Kuroo smiled. “Wouldn’t miss it.”

Kenma nodded and waved behind him as he left, likely headed to the computer science labs if Kuroo had his guess. Some of his gaming buddies were CS majors and they liked having him around to test their projects.

It was another minute before he realized Sakura-chan and Akane-chan were gaping at him. He tightened his ponytail and cleared his throat. “Is there something else I can help you with?”

A look passed between them that made him nervous. Akane-chan was the one to speak. “That was Kodzuken, right? THE Kodzuken?”

Kuroo blinked. “Yeah. Why?”

He flinched at the high-pitched squeal that escaped their throats. “Wait, so does that make you the mysterious roommate?” Sakura leaned towards him, a hungry glint to her eyes.

Kuroo shrugged, doing his best to play it cool. Would it upset Kenma if his fans knew who he was? “He’s been my friend since we were kids,” he said, figuring that was a safe enough evasion.

“Oh my god, they’re childhood friends _and_ they’re roommates,” Akane-chan whispered with awe. Kuroo was sure he didn’t like that tone.

He sat back down behind his desk with his arms folded across his chest. “If there’s nothing else I can help you with, I’m sure you girls have other classes to attend?”

Another skeptical look passed between them, but they shrugged it off and bowed their gratitude. He’d thought that would be the end of it, but their conversation as they walked out was intentionally audible enough for him to hear them. “Not sure which one is luckier,” Akane-chan sighed.

“Kodzuken really hit the jackpot with Kuroo-senpai for a boyfriend,” Sakura-chan replied. “But Kuroo-senpai also gets to go home to that beautiful man every night so maybe he’s the lucky one after all.”

Kuroo could feel his neck and face turning crimson. “He’s just my roommate!” he hollered after them. They rolled their eyes and giggled as they jogged off towards their next class. This freshman class was terrifying, he decided.

He buried his face in his hands as he sat back down at his desk. Him and Kenma? _Boyfriends?_ That was ridiculous. They’d known each other more than half their lives. They were just really good friends who lived together. They ate meals together and went out on the town together. They took care of each other when they were sick, and made sure the other was eating enough and sleeping enough. They sometimes shared a bed, and they’d had some drunken kisses, but that didn’t mean they were _a thing_ , right?

Hanako-san’s grin from that morning came back to his mind. _Same way Kenma puts up with you._

No.

No, no, no. That wasn’t it. He would know if they were dating, wouldn’t he?

His heart didn’t stop pounding for the rest of the day. He tried to blame the 5 Hour Energy he’d had with his breakfast after Sakura-chan and Akane-chan had left, but he knew the caffeine had nothing to do with it. He was a mess by the time his 1pm discussion section came around. And apparently, word had spread fast.

It took him the first 10 minutes of the time slot to get his students to focus on the lesson recap for the day. They all wanted to know what his relationship with The Awesome Kodzuken really was, and none of them wanted to accept that they were “just roommates.” He heard the “and they were roommates” line whispered and repeated to too many giggles throughout the lesson. He maintained his cool, just barely, because he was a mature TA and had dealt with several iterations of unruly freshman, but he was grateful this was his last class before the weekend. He was at his limit.

He handed back homework assignments and lab reports, the ones Kenma had so graciously brought to him before he’d even noticed they were missing, and suddenly he was anxious about his weeklyritual with his roommate.

Ritual? That didn’t feel right. It was more like a date.

Kuroo froze at the chalkboard in the middle of writing an equation. A date? That they had _weekly_?

“Kuroo-senpai?”

He shook that thought off and continued his lecture. There was no way.

Except after class he couldn’t stop thinking about it. He thought about it the whole way back to his office, where he stored the next batch of papers he had to grade, and stowed his thesis research for safe keeping—he would work on that after practice on Saturday—and his own graduate classwork. He thought about it as he walked to the business school side of campus to wait for Kenma to get out of class. He thought about it while they walked to the bakery. He thought about it as they sat at their usual table and shared the pie with two forks.

“You’re being awfully quiet this afternoon,” Kenma mused around a forkful of gooey apples and flaky pastry.

Kuroo stiffened with a jolt to his spine, his own fork halfway to his mouth, the crust flaking and threatening to succumb to gravity. “Am I?”

Kenma quirked an eyebrow and tilted his head towards him. He was wearing the forest green Zelda hoodie Kuroo had bought him for his birthday last year, the one that made his eyes shine like gold. Had his lashes always been so long? Kuroo swallowed his forkful of pie rather forcefully. “Kuroo, how long have we been together?”

Kuroo almost choked. He coughed as the pie went down harder than he expected. “What?!”

“How long have we been friends?” Kenma clarified.

Kuroo winced. “I dunno, it’s gotta be going on fifteen years by now?”

Kenma nodded. “Fifteen next month.” He took another bite of pie then set the fork down. Kuroo had never seen him put the fork down while there was still a crumb of pie left. Kenma laced his fingers together and rested his chin on them, pinning him with a calculating gaze. Kuroo had seen that look many times on a volleyball court. The look of a demon boss analyzing his enemy’s weaknesses and determining the best course of action to win. “So, when I say you’re being quiet, I am speaking from a decade and a half of experience.”

Kuroo could feel his neck and ears burning under Kenma’s scrutiny. Why was his heart pounding so hard? “I just don’t have a lot to say today.”

“Nothing?”

“Nada.”

“You never have nothing to say.”

He gulped. The pie was suddenly feeling very dry. “Today was just a little stressful,” he admitted. Ok so it was a lot stressful.

Kenma narrowed his eyes at him. “Bullshit.”

“Excuse me?”

“It’s still too early in the semester for you to be this stressed over classes or students.”

Kenma really did have his number. Kuroo licked his lips. There really was no way out of this; he was cornered. “Just cause I don’t have a mountain of coursework at the moment, it doesn’t mean I can’t be stressed.”

“It doesn’t,” Kenma agreed. “So what’s stressing you out? Is it something I can help you with?” He leaned back in his chair, folding his arms across his chest, not breaking eye contact. Kuroo could feel the sweat beading on his back. How could he ask his best friend if they were more than just best friends? How does one even broach that subject? “I’m on your side, Kuroo. You know you can talk to me about anything.”

Kuroo did know. But that didn’t make this any easier. He sighed. Maybe he was just being ridiculous, and Kenma would laugh and it would all just be a big funny joke they could look back on one day and laugh. “My students,” he sighed. “After you left, they kept insinuating that we were more than just friends, and word got around to my other section and they spent half the class asking me about you.”

Kenma’s lips pulled up in a smirk. “And you, being gracious and considerate of my reputation, denied everything, didn’t you?”

“Well,” Kuroo stammered, rubbing the back of his neck, his hair making it itch, “yeah.”

“What do you really want to ask me, Tetsuro?” Kenma’s grin was teasing, and the use of his given name gave him heart palpitations.

Honestly. Which one of them was the senior here? Kuroo swallowed his pride and asked the question that had been nagging at him since Sakura-chan and Akane-chan had voiced it that morning. “Are we dating?”

Kenma pointed a finger towards the ceiling. “Ding! We have a winner, ladies and gentleman!” He shook his head with a chuckle as he picked his fork back up and took another bite of sweet apple pie. “Have been for years, thanks for noticing.”

Kuroo blinked. Years? The last fifteen years flashed before his eyes. Their gradual descent into friendship, the late nights gaming, the quiet days where they just sat in silence together, the long volleyball practices, the heartbreaks and rejections, the happy times, graduation, their declaration to live together even after, the years of instant noodles and late-night takeout and part-time jobs, always coming home to each other, secret kisses stolen in the dark, falling asleep in one another’s arms. They even had a standing weekly date night.

He laughed, loud and obnoxious and clutching his sides. For a smart guy, he really was an idiot. “I suppose you’re right.” Kenma rolled his eyes as he took another bite of pie. Kuroo smiled, a new warmth settling in his chest.

Well, really, the warmth was nothing new. He always felt it when he watched Kenma in quiet moments. It just had a new name now. He was in love with his best friend, and they’ve been dating for years.

-

A thought occurred to Kuroo on their way to the theater. He hoped Kenma wouldn’t be too mad, but he had to at least give him a heads up. “Is it a bad time to tell you I can’t make our first date next week?”

Kenma scowled at him. “It’s not the first,” he scoffed. “But why not?”

“I was extorted into covering another lab section and won’t make it in time for pie.”

Kenma looked away from him with a small pout. He sighed exaggeratedly and said, “Just means more pie for me.” Then he gave Kuroo a sly grin. “But next time you owe me two pies.”

Kuroo laughed. “Two pies? Everyone is taking advantage of me today!” He planted a kiss on his boyfriend’s head. “Two pies then.” Kenma squeezed his hand and leaned into him. It was as natural as breathing.

**Author's Note:**

> Kuroo and Bokuto share a single braincell when it comes to their relationships and it was Bokuto's turn with the braincell to impress Akaashi this week. Also I just really love a sassy Kenma. xD
> 
> Hope you enjoyed this silly fic! Please leave kudos, comments, or come yell at me on [Twitter](https://twitter.com/anininjaspaz).


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